Process for manufacturing butyraldehyde



Patented Nov. 10, 1953 PROCESS FOR MANUFACTURING BUTYRALDEHY DE Louis Alhritiere, Beau-Soleil, Melle, France, assignor to Les Usines dc Melle (Societe Anonyme), Saint-Leger-les-Melle, France, a corporation of France No Drawing. Application August 10, 1949, Serial No. 109,610

Claims priority, application France August 20, 1948 9 Claims.

This invention relates to the manufacture of butyraldehyde by hydrogenation of crotonaldehyde.

Hydrogenation of crotonaldehyde to produce butyraldehyde is known. However, despite the care taken in conducting such operation, it has been impossible, until now, to limit the reaction to the hydrogenation of the ethylenic bond only and to avoid to a great extent the hydrogenation of the aldehydic group. As a matter of fact, the known processes always permit large quantities of butyl alcohol to be formed beside the butyraldehyde, which is the desired product.

' The principal object of the present invention is to provide an improved process for producing very high yields of butyraldehyde.

The. invention accordingly comprises the novel processes and steps of processes, specific embodiments of which are described hereinafter by way of example and in accordance withwhich I now prefer to practice the invention.

The process of the present invention, in which crotonaldehyde is hydrogenated at high temperature in the presence of a catalyst capable of hydrogenating crotonaldehyde into butyl alcohol and butyraldehyde, comprises passing over the catalyst, crotonaldehyde in admixture with butyl alcohol, the butyl alcohol being afterwards recovered and, if the operation is conducted continuously, returned to the reaction zone together with further crotonaldehyde. The catalyst is preferably a coppercatalyst, such as copper deposited on a carrier or copper-chromium catalyst.

For 1 molecule of crotonaldehyde, there are supplied to the reaction apparatus 1 to molecules, and preferably 2 to 3 molecules, of butyl alcohol, together with 1 to 2 molecules of hydrogen. The hydrogen, for example, may result from the dehydrogenation of ethyl alcohol.

According to a preferred embodimentof this invention, a mixture of crotonaldehyde, butyl alcohol and hydrogen is passed over a copper catalyst maintained at about 150-220 C. and preferably at 150-200 C. In this way, more than 95% of the crotonaldehyde employed can be transformed; the amount of butyl alcohol that is formed is very small and, when the operation is effected under the best conditions,

rated with water, for example, the crotonaldehyde which forms the upper layer by the decantation of the azeotropic mixture of Water and crotonaldehyde, obtained by distillation of the raw product of the crotonization of acetaldol, as set forth in applicants copending application Serial No. 727,491, filed February 10, 1947, now Patent No. 2,489,608, for example.

The raw product of the hydrogenation of the crotonaldehyde prepared in accordance with the present invention is fractionated by distillation: From the head of a first column one withdraws, on the one hand, aqueous butyraldehyde containing 95-96% of butyraldehyde, and on the other hand, water containing small quantities of butyraldehyde which are recovered by distillation in an exhausting column. At the foot of the first column, an anhydrous mixture of butyl alcohol, unconverted crotonaldehyde and products having higher boiling points, is collected and sent into a second column from the head of which anhydrous butyl alcohol and unconverted crotonaldehyde are withdrawn, and at the foot of which are collected the higher products (higher boiling products), which may contain or not contain small quantities of butyl alcohol, according to the conditions of distillation. The anhydrous butyl alcohol and unconverted crotonaldehyde are returned to the hydrogenation apparatus. The mixture of higher products and (eventually) butyl alcohol may be separated into its elements by distillation.

Of course, if the hydrogenation apparatus is supplied with anhydrous crotonaldehyde instead of aqueous crotonaldehyde, anhydrous butyraldehyde is obtained .at the head of the first column, instead of aqueous butyraldehyde.

The following Examples 1 and 2 represent the process in accordance with the present invention as I now prefer to practice it. It is to be understood thattheseexamples are illustrative and the invention is notto be considered as limited thereto except as 'indicatedin the appended ;claims.- In Examples A and B below, processes I are given for purposes of comparison which are not in accordance with the present invention, in order to emphasize the advantages realized in thepractice of the invention.

EXAMPLE 1 lution of copper nitrate, containing kieselguhr 1 in suspension therein. The copper hydroxide precipitates on the kieselg'uhr which is afterwards filtered off and washed. The kieselguhrcopper hydroxide mass is pelleted and reacted with hydrogen to reduce the copper hydroxide to metallic copper. This reduction is effected in the hydrogenation furnace in which the crotchaldehyde is to be hydrogenated.

Into the hydrogenation furnace, containing 120 liters of copper catalyst pellets obtained as above, and which is maintained at a temperature of 165 (3., one introduces continuouslyper hour:

45 liters of crotonaldehyde saturated with water,

i. e., 35 kgs. of pure crotonaldehyde; 92 liters of anhydous butyl alcohol recovered from a previous operation and containing about;

74 kgs. of butyl alcohol and 0.7 kg. of crotonaldehyde, and 17 cubic meters of hydrogen. Thus, the actual crotonaldehyde feed is 35.7 kgs.

per hour.

The mixture of gases and vapors flowing out. of the hydrogenation furnace is submitted to condensation by cooling, then to scrubbing for recovering the-valuable products which have not been condensed. It is to be noted-that the scrublbing may be omitted if the. condensation opera- From thehead of the second column, one

draws offper hour an anhydrous mixture of '74 kgs. of butyl alcohol and 0.? kg. of crotonaldehyde, which mixture isv returned to the hydrogenation furnace with furthercrotonaldehyde.

At the foot of the second column, one collects -per hour a mixture of 0.33. kg. of anhydrous butyl alcohol and 2.6 kgs. of products boiling from 130 to 220? C.

Y Of thBBSHkg-S. of cro tonaldehyde fed into the hyd qgenationiurnace, 35 kgs. have been transformed; the transformation ratio-is:

lows: v

. Yield, percent 32.6 kgs. of pure butyraldehyde corresponding to 31.7 kgs, t, crotonaldehyde 90.9 0.33 kg. of anhydrous butyl alcoholv correspondmg to 0.315 kg. of crotonaldehyde 2.6 kgs. of higher boiling products correspondingto 2,49kgs. of crotonaldehyde 7.1

Total yield 98.9

.' No decrease of the activity of the catalyst has been observed afterrlOOD hours of working.

I describe below an operation which is conducted in the same apparatus and exactly under Cil as above and maintained at 165 0., one introduces per hour:

46-liters of crotonaldehyde saturated with water,

i. e., 35.7-kgs.'of pure crotonaldehyde, and 17 cubic meters of hydrogen.

The reaction products are submitted to the separation asabove described under Example 1,

The balance sheetof theoperation os as 01- the same conditions as above, but without incontaining 120 liters of copper catalyst pellets and the results of the distillation are as follows:

From the head of the first column, one draws off per hour 20.8 kgs. of aqueous butyraldehyde containing 95.6% butyraldehyde by weight, i. e., 19.9 kgs. of pure butyraldehyde.

From the head of the second column, one draws offper hour 6.8 kgs. of unconverted crotonaldehyde.

At the foot of the second column, one collects per hour 9.4 kgs. of a mixture containing 2.2 kgs. of butyl alcohol and 7.2 kgs. of higher products.

0f the 35.7 kgs. of crotonaldehyde fed into the hydrogenation furnace,y28.9 kgs. have been transformed; the transformation ratio is:

The balance sheet of the operationis as .follows:

, Yield, percent 19.9 kgs or pure butyraldehyde,corresponding; to

19.4 kgs. of crotonaldehyde 67.0

2.2 kgs. of anhydrousbutyl alcohol corresponding to 2.08 kgs. of crotonaldehyde 7.2 kgs. of higher boiling1 products corresponding to 7.0 kgs. of crotonalde yde Total yield 93.4

hyde, and decrease the rate of feed of hydrogen.

However, I have found that, even under these conditions, the results that areobtained are still far below those obtained-when working-in the presence of .previouslyintroduced butyl alcohol according to the present invention; such a-comparative experiment is illustrated as follows:

Example B.Into the hydrogenation furnace, containing liters ofcopper catalyst pellets as above and maintained at 0., one introduces per hour:

100.- liters. of crotonaldehyde saturated with water, i. e., '78 kgs. of purecrotonaldehyde, and 32 cubicmeters of-hydrogen.

After condensation andscrubbingof the ,reaction products, 6. to 'Zcubicmeters of purehydrogen are recovered per hour.

w The reaction products. are submitted to distillation as above, the results of. which are ,as follows? From the head of. the first column, onedraws oif per hour 57.5 kgs. of butyraldehyde saturated with water, containing 95.6% butyraldehyde by weight, i. e., 55 kgsof pure butyraldehyde.

' From the head of the second column, one draws off per hour 9 kgs. of unconverted crotonaldehyde, which one returns to the hydrogena- The balance sheet of the operation is as follows:

' Yield, b t 1d h d I (11 t 53 gereent 55 k of pure u yra e y e correspon ng o kg of crotonaldehyde 77.2 4.85 kgs. of anhydrous butyl alcohol corresponding to 4.6 kgs. of crotonaldehyde 10.6 kgs. of higher boiling products corresponding to 10.2 kgs. of crotonaldehyde 14.8 Total yield 98.7

The length of life of the catalyst in both Examples A and B is considerably smaller than its length of life when working in the presence of previously-introduced butyl alcohol: After 180 hours of working in the conditions just described in Example B, one ascertains a sudden fall of the transformation ratio down below 60%. A similar decrease occurs with Example A.

The advantage of the process of the invention a is then evident, since this process provides:

A transformation ratio of 98% as against 88%;

A yield in butyraldehyde of 90.9% as against 77.2%;

A yield in butyl alcohol of only 0.9% as against 6.7%, and since it permits, on the other hand, of increasing ten times or more the life of the catalyst.

EXAMPLE 2.

The copper catalyst that is used is a copperchromium catalyst prepared by reacting in the heat, sodium hydroxide with an aqueous solution of copper nitrate and chromium chloride (the weight of chromium being with respect to the weight of copper), containing kieselguhr in suspension therein. The copper and chromium hydroxides precipitate on the kieselguhr which is afterwards treated as described in Ex ample 1 above.

Into the hydrogenation furnace, containing 120 liters of copper-chromium catalyst pellets obtained as has just been described, and which is maintained at a temperature of 160 C, one introduces continuously per hour:

50 liters of crotonaldehyde saturated with water,

i. e., 39 kgs. of pure crotonaldehyde;

90 liters of anhydrous butyl alcohol recovered from a previous operation and containing 72 kgs. of butyl alcohol and 1 kg. of crotonaldehyde, and 18 cubic meters of hydrogen.

with water, containing 95.6%.. butyraldehyde by weight, 1. e., 36.8 kgs. of pure butyraldehyde. From the head of the second column, one draws off per houran anhydrous mixture of 72 kgs. of butyl alcohol and 1 kg. of crotonaldehyde; which mixture is returned to the hydrogenation furnace with further crotonaldehyde.

At the foot of the second colunm,'one collects per hour a mixtureof about 0.5 kg..of anhydrous butyl alcohol and about 3 kgs. of DIOdllCtSbOfl-r. ing from to 220 ,C. I Of the 40 kgs. of crotonaldehyde fed into the hydrogenation furnace, 39 kgs. have been trans-t formed; the transformation ratio is;-

The balance sheet of the operation is as fol-- lows:

Yield,

percent 36.8 kgs. of pure butyraldehyde corresponding to 35.3 kgs. of crotonaldehyde 0.5 kg. of anhydrous butyl alcohol corresponding to 0.47 kg. of crotonaldehyde 1.2 8 kgs. 0 higher boiling 111) 2.88 kgs. of crotonalde yde 7.4

Total yield 98.9

What I claim is:

1. A process which comprises heating a mixture of crotonaldehyde, butyl alcohol and hydrogen at a temperature above the boiling point of the mixture thereof in the presence of a copper base catalyst, said butyl alcohol being present in the proportion of at least 1 mole of butyl alcohol to 1 mole of crotonaldehyde and converting the crotonaldehyde into butyraldehyde.

2. A process which comprises passing a mixture of crotonaldehyde, butyl alcohol and hydrogen over a heated copper base catalyst at a temperature above the boiling point of the mixture thereof, said butyl alcohol being present in the proportion of at least 1 mole of butyl alcohol to 1 mole of crotonaldehyde, converting the crotonaldehyde substantially completely into butyraldehyde, and separating the butyraldehyde from the butyl alcohol after passage of the mixture over the catalyst.

3. A process which comprises continuously passing a mixture of crotonaldehyde, butyl a1cohol and hydrogen over a copper base catalyst at a temperature above the boiling point of the mixture thereof, said butyl alcohol being present in the proportion of at least 1 mole of butyl alcohol to 1 mole of crotonaldehyde continuously recovering butyraldehyde and butyl alcohol from the resulting mixture, continuously returning the butyl alcohol for mixture with a further amount of crotonaldehyde and hydrogen and continuously passing such mixture over the catalyst.

4. A process in accordance with claim 3, in which the mixture of crotonaldehyde, butyl alcohol and hydrogen contains 1 to 5 molecules of butyl alcohol to 1 molecule of crotonaldehyde.

5. A process which comprises continuously passing a mixture of crotonaldehyde, butyl alcohol and hydrogen at a temperature of about C. to 220 C. over a copper base catalyst capable of hydrogenating crotonaldehyde to form butyraldehyde and butyl alcohol, said butyl alcohol being present in the proportion of at least 1 mole of butyl alcohol to 1 mole of crotonaldehyde continuously recovering butyraldehyde and butyl alcohol from the resulting mixture, continuously returning the butyl alcohol for mixture with a further amount of crotonaldehyde 7 and-(hydrogen, and .continuouslyrpa'ssing such mixture .over' theicatalyst.

6. A: process which comprises continuously passing a mixture of crotonaldehyde,-butyl alcoholandhydrogen at a temperature of about 150 C. to-200 C. over a copperbase catalyst capable of hydrogenating crotonaldehyde to form butyr- Aldchyde :and butyl alcohol -saidx mixture containing 2 to 3 molecules or butyl alcoholto 1 molecursor crotonaldehyde treated, continuouslyere- 1 8 93 A process in accordance with claim 3, m which crotonaldehyde saturated with water is employed.

LOUIS ALHERI'HERE.

References Cited in the fileof this patent UNITED STATES PATENTS Number Name Date 1,788,896 Swallen Jan. 13, 1931 2,501,708 Bewley et a1. Mar. 28, 1950 FOREIGN PATENTS Number Country Date Y 147,118 Great Britain Nov. 7, 1921 .:.362,537 Germany Oct. 28, 192 2 ,-700,935 *"France "Mar. 9,1931

- o'rnsrtinmnencss Berkman' et a1. Qatalysis" (1940) pas s 825-'6.

' Reinhold Publishing Corp.. New York. 

1. A PROCESS WHICH COMPRISES HEATING A MIXTURE OF CROTONALDEHYDE, BUTYL ALCOHOL AND HYDROGEN AT A TEMPERATURE ABOVE THE BOILING POINT OF THE MIXTURE THEREOF IN THE PRESENCE OF A COPPER BASE CATALYST, SAID BUTYL ALCOHOL BEING PRESENT IN THE PROPORTION OF AT LEAST 1 MOLE OF BUTYL ALCOHOL TO 1 MOLE OF CROTONALDEHYDE AND CONVERTING THE CROTONALDEHYDE INTO BUTYRALDEHYDE. 